Clutch and gear arrangement for a front wheel drive vehicle

ABSTRACT

A front wheel drive transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes a sun gear member, a planet carrier member, and a ring gear member. The torque transmitting devices include clutches and a brake arranged within a transmission housing. Each of the clutches and the brake are located within specific areas defined by the planetary gear sets and the housing walls.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission configuredfor a front wheel drive vehicle having eight or more speeds, five torquetransmitting devices, and four planetary gear sets.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of a pluralityof torque transmitting mechanisms, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

In one aspect of the present invention, a transaxle is provided having atransmission input member, a transmission output member, a plurality ofplanetary gear sets, and a plurality of torque-transmitting mechanisms.

In another aspect of the present invention, the transmission includes ahousing having a first wall, a second wall, and a third wall extendingbetween the first and second walls. First, second, third and fourthplanetary gear sets are disposed within the housing. Each planetary gearset includes a sun gear member, a ring gear member, and a planet carriermember supporting a plurality of planet gears each configured tointermesh with both the sun gear member and the ring gear member. Thering gear member of the first planetary gear set is permanently coupledto the sun gear member of the second planetary gear set, the ring gearmember of the second planetary gear set is permanently coupled to theplanet carrier member of the third planetary gear set, the ring gearmember of the third planetary gear set is permanently coupled to theplanet carrier member of the fourth planetary gear set, the sun gearmember of the third planetary gear set is permanently coupled to the sungear member of the fourth planetary gear set, the output member ispermanently coupled with the carrier member of the fourth planetary gearset, the input member is permanently coupled with the carrier member ofthe first planetary gear set, and the sun gear member of the firstplanetary gear set is permanently coupled to the housing.

In another aspect of the present invention, the housing has a first areadefined radially inward from an outer periphery of the planetary gearsets and axially bounded by the first wall and the first planetary gearset, a second area defined radially inward from the outer periphery ofthe planetary gear sets and axially bounded by the first and secondplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the secondand third planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the third and fourth planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the fourth planetary gear set and the second wall,and a sixth area defined radially inward from the third wall andradially outward from the outer periphery of the planetary gear sets andaxially bounded by the first wall and the second wall. A first clutch isdisposed in at least one of the first, second, third, fourth, fifth, andsixth areas, a second clutch is disposed in at least one of the first,second, third, fourth, and sixth areas, a third clutch is disposed in atleast one of the second, third, fourth, fifth and sixth areas, a fourthclutch is disposed in at least one of the second, third, fourth, andsixth areas, and a brake is disposed in at least one of the first,second, third, fourth, fifth, and sixth areas.

In yet another aspect of the present invention, a first clutch isdisposed in at least one of the first, second, third, fourth, fifth, andsixth areas, a second clutch is disposed in at least one of the first,second, third, fourth, and sixth areas, a third clutch is disposed in atleast one of the second, third, fourth, fifth and sixth areas, a fourthclutch is disposed in at least one of the second, third, fourth, andsixth areas, and a brake is disposed in at least one of the first,second, third, fourth, fifth, and sixth areas.

In yet another aspect of the present invention, the housing has a firstarea defined radially inward from an outer periphery of the planetarygear sets and axially bounded by the first wall and the first planetarygear set, a second area defined radially inward from the outer peripheryof the planetary gear sets and axially bounded by the first and secondplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the secondand third planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the third and fourth planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the fourth planetary gear set and the second wall,and a sixth area defined radially inward from the third wall andradially outward from the outer periphery of the planetary gear sets andaxially bounded by the first wall and the second wall. A first clutch isdisposed in at least one of the second, third, fourth, fifth, and sixthareas, a second clutch is disposed in at least one of the first, second,and sixth areas, a third clutch is disposed in at least one of thethird, fourth, fifth and sixth areas, a fourth clutch is disposed in atleast one of the second, third, and fifth areas, and a brake is disposedin at least one of the second, third, fourth, fifth, and sixth areas.

In yet another aspect of the present invention, the housing has a firstarea defined radially inward from an outer periphery of the planetarygear sets and axially bounded by the first wall and the second planetarygear set, a second area defined radially inward from the outer peripheryof the planetary gear sets and axially bounded by the first and secondplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the firstand third planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the third and fourth planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the fourth planetary gear set and the second wall,and a sixth area defined radially inward from the third wall andradially outward from the outer periphery of the planetary gear sets andaxially bounded by the first wall and the second wall. A first clutch isdisposed in at least one of the first, second, third, fourth, fifth, andsixth areas, a second clutch is disposed in at least one of the first,second, and sixth areas, a third clutch is disposed in at least one ofthe third, fourth, fifth and sixth areas, a fourth clutch is disposed inat least one of the second, third, and sixth areas, and a brake isdisposed in at least one of the first, second, third, fourth, fifth, andsixth areas.

In yet another aspect of the present invention, the housing has a firstarea defined radially inward from an outer periphery of the planetarygear sets and axially bounded by the first wall and the second planetarygear set, a second area defined radially inward from the outer peripheryof the planetary gear sets and axially bounded by the first and secondplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the firstand third planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the third and fourth planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the fourth planetary gear set and the second wall,and a sixth area defined radially inward from the third wall andradially outward from the outer periphery of the planetary gear sets andaxially bounded by the first wall and the second wall. A first clutch isdisposed in at least one of the first, second, third, fourth, fifth, andsixth areas, a second clutch is disposed in at least one of the first,second, third, fourth, fifth, and sixth areas, a third clutch isdisposed in at least one of the third, fourth, and sixth areas, a fourthclutch is disposed in at least one of the second, third, and sixthareas, and a brake is disposed in at least one of the first, second,third, fourth, fifth, and sixth areas.

In yet another aspect of the present invention, the housing has a firstarea defined radially inward from an outer periphery of the planetarygear sets and axially bounded by the first wall and the third planetarygear set, a second area defined radially inward from the outer peripheryof the planetary gear sets and axially bounded by the third and fourthplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the fourthand second planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the second and first planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the first planetary gear set and the second wall, anda sixth area defined radially inward from the third wall and radiallyoutward from the outer periphery of the planetary gear sets and axiallybounded by the first wall and the second wall. A first clutch isdisposed in at least one of the first, second, third, and sixth areas, asecond clutch is disposed in at least one of the third, fourth, andfifth areas, a third clutch is disposed in at least one of the first,second, fifth, and sixth areas, a fourth clutch is disposed in at leastone of the first, second, fifth, and sixth areas, and a brake isdisposed in at least one of the first, second, third, and sixth areas.

In yet another aspect of the present invention, the housing has a firstarea defined radially inward from an outer periphery of the planetarygear sets and axially bounded by the first wall and the second planetarygear set, a second area defined radially inward from the outer peripheryof the planetary gear sets and axially bounded by the second and thirdplanetary gear sets, a third area defined radially inward from the outerperiphery of the planetary gear sets and axially bounded by the thirdand fourth planetary gear sets, a fourth area defined radially inwardfrom the outer periphery of the planetary gear sets and axially boundedby the fourth and first planetary gear sets, a fifth area definedradially inward from the outer periphery of the planetary gear sets andaxially bounded by the first planetary gear set and the second wall, anda sixth area defined radially inward from the third wall and radiallyoutward from the outer periphery of the planetary gear sets and axiallybounded by the first wall and the second wall. A first clutch isdisposed in at least one of the first, second, third, and sixth areas, asecond clutch is disposed in at least one of the first, third, fourth,and sixth areas, a third clutch is disposed in at least one of thefourth, fifth, and sixth areas, a fourth clutch is disposed in at leastone of the second, third, fourth, fifth, and sixth areas, and a brake isdisposed in at least one of the first, second, third, fourth, and sixthareas.

In yet another aspect of the present invention, the clutches and thebrake are selectively engageable to establish at least eight forwardspeed ratios and at least one reverse speed ratio between the inputmember and the output member.

In yet another aspect of the present invention, the first clutch isselectively engageable to interconnect the planet carrier member of thesecond planetary gear set with the ring gear member of the fourthplanetary gear set, the second clutch is selectively engageable tointerconnect the planet carrier member of the second planetary gear setwith the planet carrier member of the first planetary gear set and theinput member, the third clutch is selectively engageable to interconnectthe planet carrier member of the first planetary gear set and the inputmember with the sun gear members of the third and fourth planetary gearsets, the fourth clutch is selectively engageable to interconnect thering gear member of the first planetary gear set and the sun gear memberof the second planetary gear set with the sun gear members of the thirdand fourth planetary gear sets, and the brake is selectively engageableto interconnect the ring gear member of the fourth planetary gear set tothe housing.

In yet another aspect of the present invention, the transaxle includes atransfer gear train having a first transfer gear intermeshed with asecond transfer gear, wherein the first transfer gear is rotatably fixedto the output member and the second transfer gear is rotatably fixed toan intermediate shaft, a differential gear set for driving a pair ofroad wheels, a pinion gear rotatably fixed to the intermediate shaft,and an input differential gear in mesh with the pinion gear andconfigured to rotatably drive the differential gear set.

In yet another aspect of the present invention, the transaxle includes apower transfer assembly having a first transfer gear and a secondtransfer gear, wherein the first transfer gear is rotatably fixed to theoutput member and the second transfer gear is rotatably fixed to a driveshaft, a power transfer member rotatably coupling the first and secondtransfer gears for transferring rotational energy from the firsttransfer gear to the second transfer gear, a final drive planetary gearset coupled to the drive shaft for receiving a driving torque from thesecond transfer gear, and a differential gear set coupled to the finaldrive planetary gear set and to a pair of road wheels for receiving afinal drive rotational torque and transferring the final drive torque tothe pair of road wheels.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1A is a schematic diagram of a gear arrangement for a front wheeldrive transmission according to the principles of the present invention;

FIG. 1B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 1A, in accordance with the embodiments of the presentinvention;

FIG. 2A is another schematic diagram of a gear arrangement for a frontwheel drive transmission according to the principles of the presentinvention;

FIG. 2B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 2A, in accordance with the embodiments of the presentinvention;

FIG. 3A is another schematic diagram of a gear arrangement for a frontwheel drive transmission according to the principles of the presentinvention;

FIG. 3B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 3A, in accordance with the embodiments of the presentinvention;

FIG. 4A is another schematic diagram of a gear arrangement for a frontwheel drive transmission according to the principles of the presentinvention;

FIG. 4B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 4A, in accordance with the embodiments of the presentinvention;

FIG. 5A is another schematic diagram of a gear arrangement for a frontwheel drive transmission according to the principles of the presentinvention;

FIG. 5B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 5A, in accordance with the embodiments of the presentinvention;

FIG. 6A is another schematic diagram of a gear arrangement for a frontwheel drive transmission according to the principles of the presentinvention;

FIG. 6B is a chart showing the locations of the torque transmittingdevices for the arrangement of planetary gear sets of the transmissionshown in FIG. 6A, in accordance with the embodiments of the presentinvention;

FIG. 7 is a schematic diagram of a front wheel drive transaxlearrangement incorporating the gear arrangement of the transmission ofFIGS. 1A-6A, according to the principles of the present invention; and

FIG. 8 is another schematic diagram of a front wheel drive transaxlearrangement incorporating the gear arrangement of the transmission ofFIGS. 1A-6A, according to the principles of the present invention.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

Referring now to FIG. 1A, an embodiment of a front wheel drivemulti-speed or eight speed transmission is generally indicated byreference number 10. The transmission 10 is illustrated as a front wheeldrive or transverse transmission, though various other types oftransmission configurations may be employed. The transmission 10includes a transmission housing 12, an input shaft or member 14, anoutput shaft or member 16 and a gear arrangement 18. The input member 14is continuously connected to an engine (shown in FIGS. 7 and 8) or to aturbine of a torque converter (not shown). The output member 16 iscontinuously connected with a final drive unit (not shown) or transfercase (shown in FIGS. 7 and 8).

The gear arrangement 18 of transmission 10 includes a first planetarygear set 20, a second planetary gear set 22, a third planetary gear set24, and a fourth planetary gear set 26. The planetary gear sets 20, 22,24 and 26 are connected between the input member 14 and the outputmember 16.

In a preferred embodiment of the present invention, the planetary gearset 20 includes a sun gear member 20C, a ring gear member 20A, and aplanet carrier member 20B that rotatably supports a set of planet orpinion gears 20D (only one of which is shown). The sun gear member 20Cis connected to transmission housing 12 with a first shaft orintermediate member 42. The ring gear member 20A is connected for commonrotation with a second shaft or intermediate member 44. The planetcarrier member 20B is connected for common rotation with input shaft ormember 14 and a third shaft or intermediate member 46. The pinion gears20D are configured to intermesh with the sun gear member 20C and thering gear member 20A.

The planetary gear set 22 includes a ring gear member 22A, a planetcarrier member 22B that rotatably supports a set of planet or piniongears 22D and a sun gear member 22C. The ring gear member 22A isconnected for common rotation with a fourth shaft or intermediate member48. The sun gear member 22C is connected for common rotation with thesecond shaft or intermediate member 44. The planet carrier member 22B isconnected for common rotation with a fifth shaft or intermediate member50. The pinion gears 22D are configured to intermesh with the sun gearmember 22C and the ring gear member 22A.

The planetary gear set 24 includes a ring gear member 24A, a planetcarrier member 24B that rotatably supports a set of planet or piniongears 24D and a sun gear member 24C. The ring gear member 24A isconnected for common rotation with a sixth shaft or intermediate member52. The sun gear member 24C is connected for common rotation with aseventh shaft or intermediate member 54. The planet carrier member 24Bis connected for common rotation with the fourth shaft or intermediatemember 48. The pinion gears 24D are configured to intermesh with the sungear member 24C and the ring gear member 24A.

The planetary gear set 26 includes a sun gear member 26C, a ring gearmember 26A, and a carrier member 26B that rotatably supports a set ofplanet or pinion gears 26D. The sun gear member 26C is connected forcommon rotation with the seventh shaft or intermediate member 54. Thering gear member 26A is connected for common rotation with an eighthshaft or intermediate member 56. The planet carrier member 26B isconnected for common rotation with the output shaft or member 16 and thesixth shaft or intermediate member 52. The pinion gears 26D areconfigured to intermesh with the sun gear member 26C and the ring gearmember 26A.

The transmission 10 also includes a plurality of torque-transmittingmechanisms or devices including a first clutch 28, a second clutch 30, athird clutch 32, a fourth clutch 34 and a brake 36. The first clutch 28is selectively engagable to connect the fifth shaft or intermediatemember 50 to the eighth shaft or intermediate member 56. The secondclutch 30 is selectively engagable to connect the input shaft or member14 and the third shaft or interconnecting member 46 to the fifthintermediate member 50. The third clutch 32 is selectively engagable toconnect the third intermediate member 46 and the input member 14 to theseventh intermediate shaft or member 54. The fourth clutch 34 isselectively engagable to connect the second shaft or intermediate member44 to the seventh shaft or intermediate member 54. Finally, the brake 36is selectively engagable to connect the eighth intermediate member 56 tothe transmission housing 12 to restrict rotation of the member 56relative to the transmission housing 12.

The transmission 10 is capable of transmitting torque from the inputshaft or member 14 to the output shaft or member 16 in at least eightforward torque ratios and one reverse torque ratio. Each of the forwardtorque ratios and the reverse torque ratio are attained by engagement ofone or more of the torque-transmitting mechanisms (i.e. first clutch 28,second clutch 30, third clutch 32, fourth clutch 34 and brake 36). Thoseskilled in the art will readily understand that a different speed ratiois associated with each torque ratio. Thus, eight forward speed ratiosmay be attained by the transmission 10.

The transmission housing 12 includes a first wall or structural member102, a second wall or structural member 104 and a third wall orstructural member 106. The third wall 106 interconnects the first andsecond walls 102 and 104 to define a space or cavity 110. The inputshaft or member 14 and output shaft or member 16 are supported by thesecond wall 104 by bearings 112. The planetary gear sets 20, 22, 24 and26 and the torque-transmitting mechanisms 28, 30, 32, 34 and 36 aredisposed within cavity 110. Further, the cavity 110 has a plurality ofareas or zones A, B, C, D, E, and F in which the plurality of torquetransmitting mechanisms 28, 30, 32, 34 and 36 will be specificallypositioned or mounted, in accordance with the preferred embodiments ofthe present invention.

As shown in FIG. 1A, zone A is defined by the area or space bounded by:the first wall 102, planetary gear set 20, radially inward by areference line “L” which is a longitudinal line that is axially alignedwith the input shaft 14, and radially outward by a reference line “M”which is a longitudinal line that extends adjacent an outer diameter orouter periphery of the planetary gear sets 20, 22, 24 and 26. Whilereference line “M” is illustrated as a straight line throughout theseveral views, it should be appreciated that reference line “M” followsthe outer periphery of the planetary gear sets 20, 22, 24 and 26, andaccordingly may be stepped or non-linear depending on the location ofthe outer periphery of each of the planetary gear sets 20, 22, 24 and26. Zone B is defined by the area bounded by: planetary gear set 20, theplanetary gear set 22, radially outward by reference line “M”, andradially inward by reference line “L”. Zone C is defined by the areabounded by: the planetary gear set 22, the planetary gear set 24,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone D is defined by the area bounded by: the planetary gearset 24, the planetary gear set 26, radially outward by reference line“M”, and radially inward by reference line “L”. Zone E is defined by thearea bounded by: the planetary gear set 26, the second end wall 104,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone F is defined by the area bounded by: the first wall 102,the second wall 104, radially inward by reference line “M” and radiallyoutward by the third wall 106.

In the gear arrangement 18 of transmission 10 shown in FIG. 1A, theplanetary gear set 20 is disposed closest to the first wall 102, theplanetary gear set 26 is disposed closest to the second wall 104, theplanetary gear set 22 is adjacent the planetary gear set 20, and theplanetary gear set 24 is disposed between the planetary gear sets 22 and26. The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 1A, the first clutch 28 is disposed inZone F, the second clutch 30 is disposed in Zone A, the third clutch 32and the brake 36 are disposed in Zone E, and the fourth clutch 34 isdisposed in Zone C.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 1B. The chart of FIG. 1B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones A,B, C, D, E, or F and fourth clutch 34 may be located in zones B, C, D,or F.

Referring now to FIG. 2A, another embodiment of a transmission isgenerally indicated by reference number 100. The transmission 100 issimilar to transmission 10 and like components are indicated by likereference numbers. However, the transmission 100 includes an alternategear arrangement 118 where the first interconnecting member 42 is fixedto the top wall 106 and the second and third interconnecting members 44and 46 are nested (i.e. are sleeve shafts) with the input member 14.

The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 2A, the first clutch 28 and the secondclutch 30 are disposed in Zone B, the third clutch 32 and the brake 36are disposed in Zone E, and the fourth clutch 34 is disposed in Zone C.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 2B. The chart of FIG. 2B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones B,C, D, E, or F and fourth clutch 34 may be located in zones B, C, or E.

Referring now to FIG. 3A, another embodiment of a transmission isgenerally indicated by reference number 200. The transmission 200 issimilar to transmission 10 and like components are indicated by likereference numbers. However, as shown in FIG. 3A, zone A is defined bythe area or space bounded by: the first wall 102, planetary gear set 22,radially inward by a reference line “L” which is a longitudinal linethat is axially aligned with the input shaft 14, and radially outward bya reference line “M” which is a longitudinal line that extends adjacentan outer diameter or outer periphery of the planetary gear sets 20, 22,24 and 26. While reference line “M” is illustrated as a straight linethroughout the several views, it should be appreciated that referenceline “M” follows the outer periphery of the planetary gear sets 20, 22,24 and 26, and accordingly may be stepped or non-linear depending on thelocation of the outer periphery of each of the planetary gear sets 20,22, 24 and 26. Zone B is defined by the area bounded by: planetary gearset 22, the planetary gear set 20, radially outward by reference line“M”, and radially inward by reference line “L”. Zone C is defined by thearea bounded by: the planetary gear set 20, the planetary gear set 24,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone D is defined by the area bounded by: the planetary gearset 24, the planetary gear set 26, radially outward by reference line“M”, and radially inward by reference line “L”. Zone E is defined by thearea bounded by: the planetary gear set 26, the second end wall 104,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone F is defined by the area bounded by: the first wall 102,the second wall 104, radially inward by reference line “M” and radiallyoutward by the third wall 106.

In the gear arrangement 218 of transmission 200 shown in FIG. 3A, theplanetary gear set 22 is disposed closest to the first wall 102, theplanetary gear set 26 is disposed closest to the second wall 104, theplanetary gear set 20 is adjacent the planetary gear set 22, and theplanetary gear set 24 is disposed between the planetary gear sets 20 and26. The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 3A, the first clutch 28 and the brake36 are disposed in Zone F, the second clutch 30 is disposed in Zone A,the third clutch 32 and the fourth clutch 34 are disposed in Zone C.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 3B. The chart of FIG. 3B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones A,B, C, D, E, or F and fourth clutch 34 may be located in zones B, C, orF.

Referring now to FIG. 4A, another embodiment of a transmission isgenerally indicated by reference number 300. The transmission 300 issimilar to transmission 200 and like components are indicated by likereference numbers. However, the transmission 300 includes an alternategear arrangement 318 where the first interconnecting member 42 is fixedto the wall 104 and the location of the third interconnecting member 46and the input member 14 are switched relative to planetary gear set 20.

The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 4A, the first clutch 28 is disposed inZone F, the second clutch 30 is disposed in Zone A, the third clutch 32and the fourth clutch 34 are disposed in Zone C, and the brake 36 isdisposed in Zone E.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 4B. The chart of FIG. 4B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones A,B, C, D, E, or F and fourth clutch 34 may be located in zones B, C, orF.

Referring now to FIG. 5A, another embodiment of a transmission isgenerally indicated by reference number 400. The transmission 400 issimilar to transmission 10 and like components are indicated by likereference numbers. However, as shown in FIG. 5A, Zone A is defined bythe area or space bounded by: the first wall 102, planetary gear set 24,radially inward by a reference line “L” which is a longitudinal linethat is axially aligned with the input shaft 14, and radially outward bya reference line “M” which is a longitudinal line that extends adjacentan outer diameter or outer periphery of the planetary gear sets 20, 22,24 and 26. While reference line “M” is illustrated as a straight linethroughout the several views, it should be appreciated that referenceline “M” follows the outer periphery of the planetary gear sets 20, 22,24 and 26, and accordingly may be stepped or non-linear depending on thelocation of the outer periphery of each of the planetary gear sets 20,22, 24 and 26. Zone B is defined by the area bounded by: planetary gearset 24, the planetary gear set 26, radially outward by reference line“M”, and radially inward by reference line “L”. Zone C is defined by thearea bounded by: the planetary gear set 26, the planetary gear set 22,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone D is defined by the area bounded by: the planetary gearset 22, the planetary gear set 20, radially outward by reference line“M”, and radially inward by reference line “L”. Zone E is defined by thearea bounded by: the planetary gear set 20, the second end wall 104,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone F is defined by the area bounded by: the first wall 102,the second wall 104, radially inward by reference line “M” and radiallyoutward by the third wall 106.

In the gear arrangement 418 of transmission 400 shown in FIG. 5A, theplanetary gear set 24 is disposed closest to the first wall 102, theplanetary gear set 20 is disposed closest to the second wall 104, theplanetary gear set 26 is adjacent the planetary gear set 24, and theplanetary gear set 22 is disposed between the planetary gear sets 26 and20. The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 5A, the first clutch 28 and the brake36 are disposed in Zone F, the second clutch 30 is disposed in Zone D,and the third clutch 32 and the fourth clutch 34 are disposed in Zone E.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 5B. The chart of FIG. 5B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones A,B, C, or F and fourth clutch 34 may be located in zones A, B, E, or F.

Referring now to FIG. 6A, another embodiment of a transmission isgenerally indicated by reference number 500. The transmission 500 issimilar to transmission 10 and like components are indicated by likereference numbers. However, as shown in FIG. 6A, Zone A is defined bythe area or space bounded by: the first wall 102, planetary gear set 22,radially inward by a reference line “L” which is a longitudinal linethat is axially aligned with the input shaft 14, and radially outward bya reference line “M” which is a longitudinal line that extends adjacentan outer diameter or outer periphery of the planetary gear sets 20, 22,24 and 26. While reference line “M” is illustrated as a straight linethroughout the several views, it should be appreciated that referenceline “M” follows the outer periphery of the planetary gear sets 20, 22,24 and 26, and accordingly may be stepped or non-linear depending on thelocation of the outer periphery of each of the planetary gear sets 20,22, 24 and 26. Zone B is defined by the area bounded by: planetary gearset 22, the planetary gear set 24, radially outward by reference line“M”, and radially inward by reference line “L”. Zone C is defined by thearea bounded by: the planetary gear set 24, the planetary gear set 26,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone D is defined by the area bounded by: the planetary gearset 26, the planetary gear set 20, radially outward by reference line“M”, and radially inward by reference line “L”. Zone E is defined by thearea bounded by: the planetary gear set 20, the second end wall 104,radially outward by reference line “M”, and radially inward by referenceline “L”. Zone F is defined by the area bounded by: the first wall 102,the second wall 104, radially inward by reference line “M” and radiallyoutward by the third wall 106.

In the gear arrangement 518 of transmission 500 shown in FIG. 6A, theplanetary gear set 22 is disposed closest to the first wall 102, theplanetary gear set 20 is disposed closest to the second wall 104, theplanetary gear set 24 is adjacent the planetary gear set 22, and theplanetary gear set 26 is disposed between the planetary gear sets 24 and20. The torque-transmitting mechanisms are intentionally located withinspecific Zones in order to provide advantages in overall transmissionsize, packaging efficiency, and reduced manufacturing complexity. In theparticular example shown in FIG. 6A, the first clutch 28 and the secondclutch 30 are disposed in Zone A, the third clutch 32 and the fourthclutch 34 are disposed in Zone E, and the brake is disposed in Zone F.

However, the present invention contemplates other embodiments where thetorque-transmitting mechanisms 28, 30, 32, 34 and 36 are disposed in theother Zones. The feasible locations of the torque-transmittingmechanisms 28, 30, 32, 34 and 36 within the Zones are illustrated in thechart shown in FIG. 6B. The chart of FIG. 6B lists clutches and thebrake in the left most column and the available zones to locate theclutch/brake in the top row. An “X” in the chart indicates that thepresent invention contemplates locating the clutch or brake in the zonelisted in the top row. For example, brake 36 may be located in Zones A,B, C, D, or F and fourth clutch 34 may be located in zones B, C, D, E,or F.

Referring now to FIG. 7, a front wheel drive powertrain 600incorporating a transaxle 602 is illustrated, in accordance with theembodiments of the present invention. Transaxle 602 includes thetransmission 10 having the gear arrangement 18 shown in FIGS. 1A and 1B.However, it should be appreciated that the transaxle 602 may incorporateany of the transmissions 10, 100, 200, 300, 400, and 500 having any ofthe gear arrangements 18, 118, 218, 318, 418, and 518 shown in FIGS. 1Athrough 6B without departing from the scope of the present invention.Transmission 10 is mounted to an engine 604. Engine 604 provides adriving torque through input shaft 14 to transmission 10. Engine 604 isgenerally an internal combustion engine, however, the present inventioncontemplates other types of engines such as electric and hybrid engines.Further, transaxle 602 includes a transfer gear train 606, adifferential 608, and a pair of drive axles 610 and 612 that drive apair of road wheels 614 and 616, respectively.

Transfer gear train 606 includes a first transfer gear 618 and a secondtransfer gear 620. Output shaft or member 16 is coupled to the firsttransfer or spur gear 618. First transfer gear 618 may be a straightspur gear having straight gear teeth or a helical gear having helicalgear teeth. First transfer gear 618 meshes with the second transfer gear620. Second transfer gear 620 is rotatably fixed to an intermediateshaft or rotatable member 622. Further, a pinion 624 is mounted to shaft622 and intermeshes with an input differential gear 626. Inputdifferential gear 626 transfers driving torque to the differential 608.Differential 608, as conventionally known, transfers the driving torquegenerated by engine 604 to the two drive axles 610 and 612. Drive axles610 and 612 are independently driven by differential 608 to supply thedriving torque to the vehicle road wheels 614 and 616.

Referring now to FIG. 8, another embodiment of a front wheel drivepowertrain 700 incorporating a transaxle 702 is illustrated, inaccordance with the embodiments of the present invention. Transaxle 702includes the transmission 10 having the gear arrangement 18 shown inFIGS. 1A and 1B. However, it should be appreciated that the transaxle702 may incorporate any of the transmissions 10, 100, 200, 300, 400, and500 having any of the gear arrangements 18, 118, 218, 318, 418, and 518shown in FIGS. 1A through 6B without departing from the scope of thepresent invention. Transmission 10 is mounted to an engine 704. Engine704 provides a driving torque through input shaft 14 to transmission 10.Further, transaxle 702 includes a transfer chain 706, a driven sprocketor gear 708, a differential 710, a final drive planetary gear set 712and a pair of drive axles 714 and 716 that drive a pair of road wheels718 and 720, respectively.

Transfer chain 706 engages at a first end 722 a drive sprocket or gear724 and at a second end 726 the driven sprocket or gear 708. The drivesprocket 724 is coupled to output shaft or member 16. Driven sprocket708 is rotatably fixed to a drive shaft or rotatable member 728.Further, drive shaft 728 is coupled to the sun gear of the final driveplanetary gear set 712 to achieve the desired gear ratio. The finaldrive planetary gear set 712 transfers driving torque to thedifferential 710 though the carrier member of the final drive planetarygear set 712 to the housing of the differential 710. Differential 710,as conventionally known, transfers the driving torque generated byengine 704 to the two drive axles 714 and 716 through bevel gears ofdifferential 710. Drive axles 714 and are independently driven bydifferential 710 to supply the driving torque to the vehicle road wheels718 and 720.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transaxle comprising: an input member; an output member; a housinghaving a first wall, a second wall, and a third wall extending betweenthe first and second walls; first, second, third and fourth planetarygear sets disposed within the housing, wherein the first planetary gearset is adjacent the first wall, the fourth planetary gear set isadjacent second wall, the second planetary gear set is adjacent thefirst planetary gear set and the third planetary gear set is between thesecond and fourth planetary gear sets, each planetary gear set having asun gear member, a ring gear member, and a planet carrier membersupporting a plurality of planet gears each configured to intermesh withboth the sun gear member and the ring gear member, and wherein the ringgear member of the first planetary gear set is permanently coupled tothe sun gear member of the second planetary gear set, the ring gearmember of the second planetary gear set is permanently coupled to theplanet carrier member of the third planetary gear set, the ring gearmember of the third planetary gear set is permanently coupled to theplanet carrier member of the fourth planetary gear set, the sun gearmember of the third planetary gear set is permanently coupled to the sungear member of the fourth planetary gear set, the output member ispermanently coupled with the carrier member of the fourth planetary gearset, the input member is permanently coupled with the carrier member ofthe first planetary gear set, and the sun gear member of the firstplanetary gear set is permanently coupled to the first wall of thehousing, and wherein the housing has a first area defined radiallyinward from an outer periphery of the planetary gear sets and axiallybounded by the first wall and the first planetary gear set, a secondarea defined radially inward from the outer periphery of the planetarygear sets and axially bounded by the first and second planetary gearsets, a third area defined radially inward from the outer periphery ofthe planetary gear sets and axially bounded by the second and thirdplanetary gear sets, a fourth area defined radially inward from theouter periphery of the planetary gear sets and axially bounded by thethird and fourth planetary gear sets, a fifth area defined radiallyinward from the outer periphery of the planetary gear sets and axiallybounded by the fourth planetary gear set and the second wall, and asixth area defined radially inward from the third wall and radiallyoutward from the outer periphery of the planetary gear sets and axiallybounded by the first wall and the second wall; a first clutch disposedin at least one of the first, second, third, fourth, fifth, and sixthareas; a second clutch disposed in at least one of the first, second,third, fourth, and sixth areas; a third clutch disposed in at least oneof the second, third, fourth, fifth and sixth areas; a fourth clutchdisposed in at least one of the second, third, fourth, and sixth areas;a brake disposed in at least one of the first, second, third, fourth,fifth, and sixth areas, and wherein the clutches and the brake areselectively engageable to establish at least eight forward speed ratiosand at least one reverse speed ratio between the input member and theoutput member; a transfer gear train having a first transfer gearintermeshed with a second transfer gear, wherein the first transfer gearis rotatably fixed to the output member and the second transfer gear isrotatably fixed to an intermediate shaft; a differential gear set fordriving a pair of road wheels; a pinion gear rotatably fixed to theintermediate shaft; and an input differential gear in mesh with thepinion gear and configured to rotatably drive the differential gear set.2. The transaxle of claim 1 wherein the first clutch is selectivelyengageable to interconnect the planet carrier member of the secondplanetary gear set with the ring gear member of the fourth planetarygear set, the second clutch is selectively engageable to interconnectthe planet carrier member of the second planetary gear set with theplanet carrier member of the first planetary gear set and the inputmember, the third clutch is selectively engageable to interconnect theplanet carrier member of the first planetary gear set and the inputmember with the sun gear members of the third and fourth planetary gearsets, the fourth clutch is selectively engageable to interconnect thering gear member of the first planetary gear set and the sun gear memberof the second planetary gear set with the sun gear members of the thirdand fourth planetary gear sets, and the brake is selectively engageableto interconnect the ring gear member of the fourth planetary gear set tothe housing.
 3. The transaxle of claim 2 wherein the first clutch isdisposed in the sixth area, the second clutch is disposed in the firstarea, the third clutch is disposed in the fifth area, the fourth clutchis disposed in the third area, and the brake is disposed in the fiftharea.